Soon after the United States Navy SEAL raid on bin Laden's house, "A Pakistani official told me the US had direct evidence that the ISI chief, Lt Gen Ahmed Shuja Pasha, knew of Bin Laden's presence in Abbottabad," the New York Times reported in an article by senior journalist Carlotta Gall.

"The information came from a senior US official, and I guessed that the Americans had intercepted a phone call of Pasha's or one about him in the days after the raid", Gall wrote in the article titled 'What Pakistan Knew About Bin Laden', adapted from the book 'The Wrong Enemy: America in Afghanistan, 2001-2014', to be published next month.

Gall covered Afghanistan and Pakistan for the paper from 2001 to 2013. "He knew of Osama's whereabouts, yes," the Pakistani official was quoted as saying.

"Pasha was always their blue-eyed boy," the official said, adding he was surprised to learn this. But in the weeks and months after the raid, Pasha and the ISI press office strenuously denied that they had any knowledge of bin Laden's presence in Abbottabad.

The haul of handwritten notes, letters, computer files and other information collected from bin Laden's house during the raid revealed regular correspondence "between Bin Laden and a string of militant leaders who must have known he was living in Pakistan, including Hafiz Muhammad Saeed, the founder of Lashkar-e-Tayiba, a pro-Kashmiri group that has also been active in Afghanistan, and Mullah Omar of the Taliban".

"Saeed and Omar are two of the ISI's most important and loyal militant leaders. Both are protected by the agency. Both cooperate closely with it, restraining their followers from attacking the Pakistani state and coordinating with Pakistan's greater strategic plans.

"Any correspondence the two men had with Bin Laden would probably have been known to their ISI handlers," it said. Bin Laden was shot dead by US commandos in May 2012 in a unilateral raid by them, catching the Pakistanis by surprise. It was always suspected that some on the Pakistani establishment knew bin Laden's whereabouts as he was living a stone- throw away from the military academy in the garrison city of Abbottabad.

"According to one inside source, the ISI actually ran a special desk assigned to handle Bin Laden. It was operated independently, led by an officer who made his own decisions and did not report to a superior. He handled only one person: Bin Laden," the daily reported.